Traditionally, the construction of the fly in trousers or the like has entailed a plurality of parts requiring rather precise cutting, matching and registration with one another. The fact is that the complexity of popular closures for trousers or the like presently requires skillful persons in order to form consistent, uniform closures acceptable to the consuming public. In view of the large amount of handling and hand labor in positioning the parts, it has been impossible to speed up this task and reduce the cost of the fly making operation.
In the manufacture of trousers or the like the common method employed is to cut front panels from the material supply and to separately cut fly flap pieces from the material supply. Slide fastener strips are then attached in predetermined position on the fly flap pieces after which the fly flap pieces are attached to the front panels in the desired position. The front panels are then attached to each other at the crotch portion with the slide fastener strip lying between the fly flap pieces.
In attaching the fly flap piece to the front panel which is to provide the outer or exposed portion of the fly structure a seam is formed along the free edge of the fly structure by the doubling back of the fly piece. This seam provides both rigidity due to the extra layers of material and also reinforcement for the fly structure.
Attempts have been made to form the fly structure from flaps which are integral with the front panels but, these structures have lacked the rigidity desired and accomplished by attaching the fly flap pieces which were separate from the panels. Various solutions to this problem including the addition of a separate strip to provide reinforcement and rigidity have proven unsatisfactory.